AMR in bacteria from humans, animals, and food in Europe
Authors: Sanjeet Bagcchi
Journal: The Lancet Microbe (2023)

On March 6, 2023, the European Centre for Disease Prevention and Control (ECDC) and the European Food Safety Authority (EFSA) released their annual report on antimicrobial resistance (AMR) in zoonotic and indicator bacteria from humans, animals, and food. The report primarily focuses on AMR in Salmonella spp and Campylobacter spp from human and food-producing animal sources and in Escherichia coli of food-producing animal origins, and collates 2020–21 data from 27 EU member states, the UK, and five additional non-member states. Salmonella spp and Campylobacter spp infections are the two most common causes of foodborne diseases in the EU. According to Therese Westrell (ECDC, Solna, Sweden), coauthor of the report, “most Salmonella and Campylobacter infections are mild and do not require treatment with antibiotics, but some patients have more severe symptoms and require antibiotic treatment. Antibiotic-resistant bacteria transmitted via food may give infections that are difficult to treat”, which underscores the importance of AMR surveillance in these bacteria. Findings in the report regarding AMR in Salmonella spp and Campylobacter spp were overall similar for human and animal sources. Resistance to ampicillin, tetracyclines, and sulfonamides in Salmonella spp ranged from moderate to very high; similar observations were made for E coli isolates from food-producing animals and poultry carcasses, whereas in Campylobacter spp of animal origin resistance to tetracyclines was high to extremely high. On a positive note, however, a decreasing trend in resistance to ampicillin and tetracyclines was observed from 2013 to 2021 in Salmonella spp isolates of human origin. Moderate to extremely high resistance to ciprofloxacin was observed in Salmonella spp, Campylobacter spp, and E coli with variations according to isolate source and species or serotype; for example, although overall resistance of human Salmonella spp isolates was moderate, Salmonella Kentuky exhibited extremely high resistance. Furthermore, increases in resistance to ciprofloxacin were recorded in Salmonella Enteritidis isolated from poultry and in Campylobacter spp isolated from humans in 2013–21. Low-to-moderate ciprofloxacin resistance was only reported for Salmonella spp and E coli isolates from pigs and calves. High resistance to fluoroquinolones such as ciprofloxacin is concerning. However, reassuringly, combined resistance to ciprofloxacin and cefotaxime (classified as highest priority critically important antibiotics) in Salmonella spp and in E coli from food-producing animals is, for now, rare, as is, mostly, combined resistance to ciprofloxacin and erythromycin in Campylobacter spp (antibiotics of high public health relevance because of their use in the treatment of human campylobacteriosis). Other reassuring highlights of the report included low resistance to third-generation cephalosporins and low prevalence of extended-spectrum beta-lactamase (ESBL) or class C beta-lactamase (AmpC) producers in most Salmonella isolates from both human and animal sources. Occurrence of ESBL and AmpC was more variable—and concerning—in E coli isolates, with several carbapenemase-producing isolates identified in pigs and bovines or in meat from these animals in several European countries. Nevertheless, during 2014–21 the prevalence in food-producing animals of ESBL-producing or AmpC-producing E coli decreased in most analysed countries and the prevalence of E coli isolates completely susceptible to the EU-defined harmonised panel of antimicrobials increased in eight countries (while only decreasing in three). These findings are indicative of recent progress in the reduction of AMR in food-producing animals in multiple European countries. Indeed, Westrell notes that “in the past years, we have…observed decreasing resistance to some of the commonly used antimicrobials in food-producing animals, most likely resulting from actions aimed at reducing the use of antimicrobials in these animals”. In June 2017, the European Commission adopted the EU One Health Action Plan against AMR, the implementation of which might have contributed to the progress identified in the report. The plan focused on encouraging judicious use of antimicrobials, strengthening cross-sectorial activities, boosting the prevention and control of infection, and consolidating monitoring of AMR and consumption of antimicrobials. According to Ramanan Laxminarayan (Center for Disease Dynamics, Economics & Policy, Washington, DC, USA), “any positive trend in terms of decreasing resistance is an opportunity to [learn] why this is happening, and increasing resistance, particularly to last resort antibiotics like carbapenems should be addressed through policy.Resistance levels in Europe are lower than in the rest of the world because of proactive policies to reduce antibiotic use in both humans and animals.” Laxminarayan also added that “Reports such as these offer hope that we can turn things around even in countries with high levels of resistance, provided we respond promptly with appropriate policies”. But Westrell cautions that “one point of concern is that resistance to some of the medically important antimicrobials used to treat foodborne infections is increasing” and believes that “we need to follow a One Health approach to ensure that antimicrobials that are critical for treatment of infections in humans are avoided in animal production and used wisely in health-care settings”. For the ECDC and EFSA report see https://www.ecdc.europa.eu/sites/default/files/documents/summary-report-antimicrobial-resistance-zoonotic-indicator-bacteria-humans-animals-food-2020-2021.pdfFor the EU One Health Action Plan against AMR see https://health.ec.europa.eu/antimicrobial-resistance/eu-action-antimicrobial-resistance_en For the ECDC and EFSA report see https://www.ecdc.europa.eu/sites/default/files/documents/summary-report-antimicrobial-resistance-zoonotic-indicator-bacteria-humans-animals-food-2020-2021.pdf For the EU One Health Action Plan against AMR see https://health.ec.europa.eu/antimicrobial-resistance/eu-action-antimicrobial-resistance_en